1. Field of the Invention
The present invention relates to a coating layer for blocking electromagnetic interference (EMI), an optical filter including the same, and a display apparatus including the same, and more particularly, to a coating layer for blocking EMI, an optical filter including the same, and a display apparatus including the same, in which excellent blocking efficiency of EMI can be obtained due to low surface resistance, and excellent regeneration can be obtained due to a low possibility of peeling.
2. Description of the Related Art
Generally, in a plasma display panel (PDP) device, a discharge is generated from a gas between electrodes by a direct current or an alternating current voltage applied to electrodes. A phosphor is excited by emission of ultraviolet rays accompanied with the discharge to emit light. Also, the PDP device has drawbacks in that a high emission rate of electromagnetic waves and near infrared rays is caused due to driving characteristics of the PDP device, surface reflection of a phosphor is high, and color purity does not reach a cathode ray tube due to orange light emitted from a sealing gas such as He or Xe.
Consequently, the electromagnetic waves and near infrared rays generated from the PDP device may adversely affect a human body and may cause malfunctions of sensitive equipment such as a wireless phone or a remote controller. To use such a PDP device, it is required that emission of the electromagnetic waves and near infrared rays emitted from the PDP device should be controlled to be at a predetermined value or less. To this end, a PDP filter is used, which has a blocking function of EMI, a blocking function of near infrared rays, antireflection function of light surface, and improvement function of color purity to block EMI and near infrared rays, reduce reflection light, and improve color purity. Accordingly, the PDP device includes a panel assembly and a PDP filter, wherein the panel assembly includes a discharge cell where gas discharge occurs, and the PDP filter blocks electromagnetic waves and near infrared rays.
Furthermore, the PDP filter should have transparency since it is fixed to a front portion of the panel assembly. Also, in the PDP device, a current flowing in a driving circuit and an alternating current electrode and a high voltage applied between electrodes for plasma discharge are main factors which generate electromagnetic waves. At this time, a main frequency area of the generated electromagnetic waves is in the range of 30 MHz to 200 MHz. A transparent conductive film or a conductive mesh is used as a blocking layer of EMI. In this case, the transparent conductive film or the conductive mesh maintains high transmissivity and low reflexibility to visible rays.
The blocking layer of EMI, which is formed of a conductive mesh, has excellent characteristics in blocking EMI. Indium tin oxide (ITO) is mainly used as a single layered conductive film. When the blocking layer of EMI is formed of a multilayered transparent conductive film of a precious metal thin film, the multilayered thin film is coated with a metal thin film and a high refraction transparent thin film alternately. At this time, Ag or an alloy which contains Ag as a main component is mainly used as the metal thin film.
The metal thin film of Ag, and the like, has excellent reflexibility characteristics when thin, but blocking efficiency of the EMI may become worse as surface resistance is reduced. A transparent conductive film structure which satisfies both reflexibility characteristics and blocking efficiency of EMI has not yet been provided.